Number System and Representation

CONCEPT NUMBERING SYSTEM

• A numbering system is a way of representing numbers.
• common numbering system used is called the decimal numbering system / base 10 numbering system.
• the decimal numbering system is the numbering system that represents all numbers using 10 symbols (0-9)

BINARY NUMBERING SYSTEM

HEXADECIMAL NUMBERING SYSTEM

• uses 16 different symbols (0-9,A,B,C,D,E,F)

2.1.3 STORAGE CAPACITY

Storage capacity  refers to how much disk space one

or more storage  devices provides.

Measured in units such as Kilobyte (KB), Megabyte 

(MB), Gigabyte (GB), Terabyte (TB), Petabyte (PB).

CONVERSION

1.Convert 1GB to KB :

1GB = 1 x 1024 x 1024      

= 1 048 576 KB

2. Convert 1200 TB to PB

1200 TB = 1200 / 1024

= 1.17 PB

Typical storage and capacities

Storage	Capacity
Tape drive	A few hundred kilobytes to several gigabytes
Diskette	1.44 MB
CD-ROM	650 MB – 700MB
Hard disks External hard disk	Up to 4TB or more

2.1.1 DATA REPRESENTATION

How computers represent data?

Data & instructions can be represented electronically by  using two unique binary digits 1 (on) and 0 (off) 

Eight bits is combined together to represent a character.

                       The Difference between Bit and Byte?


Bit

Size

(the amount of information stored) - The smallest unit of data a                                                                  computer can process that                                                                    consist 0 (off) or 1 (on).

Usage - Use to measure data transfer rate of computer                                     communications devices.(Kbps, Mbps, Gbps)

Byte

Size - Eight bits grouped together  as a unit to store a single                       character up to 256 individual characters

Usage - Use to measure storage capacity. (KB,MB,GB,TB,PB)

 CHAPTER 2

COMPUTER SYSTEM

 

•What is a Computer?

•An electronic device (machine), that performs four basic operations: input, processing, output and storage.

    OR

•An electronic device, operating under the control of instructions stored in its own memory, that:

–accept data,

–process data,

–produce results, &

–store results for future use.

A computer system is :

 
A collection of related computer components (hardware & software) that have been designed to work together smoothly.

The components of a computer : 

 hardware

The components of a computer : software

system software : programs that control or maintain the operations of a computer and its device.

Application software : program designed to make users more productive and/or assist them with personal tasks.

INFORMATION PROCESSING CYCLE

DUNIA SCIENCE COMPUTER KMS

                                

                                 INTRODUCTION TO INFORMATION                                                            TECHNOLOGY

Definition of
Information Technology

  —Information Technology (IT) is defined as the use of computer hardware and software to store, retrieve, and manipulate  information.

Advantages of Information Technology

žEasier Communication  :

—With the help of information technology, communication has also become cheaper, quicker, and more efficient. We can now communicate with anyone around the world through email, or using the social network services (Facebook, Twitter, Instagram)

ž

ž

Creation of new jobs :

—Creation of new and interesting jobs such as Computer programmers, Systems analyzers, Hardware and Software developers and Web designers are examples of new job opportunities created with the help of IT. 

žGlobalization of knowledge:

—Today you can use the internet to get the latest news from any country on the globe. Services like ‘’Twitter’’  and Wikipedia are well equipped with data on about anything.

—žImproves data storage and file management:

—Information and data are very important tools, so it is very essential to store them safely and also access them at any time of need. With services like “Dropbox”, we can store and backup data, and can access data any time any where. 

Disadvantages of Information Technology

—Social implications :

—With the increased addiction to social networks and internet games, people are spending more time on computers and give up on their normal life. 

—

—Over dependence on information  technology makes students less active and innovative:

—Students no longer take time to solve problems and tasks, all they do is query that task in a search engine and a solution will be provided.

—Unemployment :

—Information Technology has replaced most positions which humans used to take up. Accounting is now being done by software, so accountants run out of opportunities.

—

—Internet security issues :

—For  customers to perform online transactions, they have  to provide their personal details. Experienced hackers can use this lop hole to channel this information and use it for their own needs.

WHAT IS A COMPUTER ???

Computer is an electronic device operating under the control of instruction stored in its own memory that accepts data process the data, produce results and store the results for future use.

CATEGORIES OF COMPUTER

• SUPERCOMPUTERS

• MAINFRAMES

• PERSONAL COMPUTERS

• MOBILE COMPUTER AND DEVICES

• EMBEDDED COMPUTERS